Package repository

apt.armbian.com

Armbian repository contains dedicated u-boots for each board, kernels that power them and various support files. Kernel packages come with firmware, headers and on modern kernels with device tree blob packages.

beta.armbian.com

Armbian beta repository contains automated & untested daily builds. You can use armbian-config utility to switch to beta branch. Make sure you don’t do that in a production environment!